Telephone handset



Patented Oct. 3, 1944 TELEPHONE HANDSET Ernest S. McLarn, Manhasset, N.-Y., assignor to International Standard Electric Corporation, New- York,,N. Y., a corporation of Delaware Application April 13, 1942, Serial No. 438,774

13 Claims. (01. 179-103) This invention relates to telephone hand sets, and more particularly to means for connecting a multi-conductor cord to the transmitter and receiver units of such hand sets.

An object of the invention is to provide an arrangement for cording hand sets which is simple, trouble-free, effective, and cheap, and which dispenses with all inserts, screw connections, and spring contacts. A further object is to render the operation of attaching the cording a completely automatic one which permits no error in the connections and effects a substantial saving of time.

More specifically, it .is an object of my invention to provide a cording arrangement in which the cord consists of a length of flat, ribbonshaped multi-conductor cordage comprising a plurality ofparallel conductors, which is threaded in a passageway or channel formed in the supporting shell of the hand set and extending down the handle from the transmitter capsule cavity to the receiver capsule cavity. The transmitter and receiver capsules are equipped with connectors provided with prongs which pierce the cord and make electrical contact with the proper tinsel or stranded conductors when the capsules are pressed home in their cavities by the act of screwing on the transmitter and receiver caps.

The above and other objects and features of my invention will be more fully understood.- from the following description taken in conjunction with the accompanying drawing in which Fig. 1 is a sectional View of the hand set;

Fig. 2' is a section of the transmitter end of the hand set taken along the line 2-2 of Fig. 1;

Fig. 3 is a section of the handle of the hand set taken along the line 33 of Fig. 1;

Fig. 4 is a section of the receiver end of the hand set taken along the line 4-4 of Fig. 1;

' Fig. 5 is a bottom view of the transmitter capsule; and

Fig. 6 is a bottom view of the receiver capsule.

Referring more particularly to Figs. 1 to 4, the hand set comprises a supporting shell I of molded thermoplastic material formed with a handle portion and two enlarged ends provided with cavities 2 and 3 for accommodating a transmitter capsule 6 and a receiver capsule I. In

the supporting shell I is a passageway or channel 4 which is open at the end at which the transmitter is located and extends from the base of the transmitter cavity through the handle portion to the base of the receiver cavity.

The cord 5 comprises three parallel tinsel or stranded conductors covered with a braided or knitted fabric covering and vulcanized in a rub-' ber insulation ribbon, the three conductors 1ying in a substantially common plane. One of the flat sides of the ribbon is formed with a longitudinally extending rib or ridge to ensure that the cord can be inserted in a hole of similar cross section in one correct way only whereby the different conductors will be connected to the proper connectors provided on the transmitter and receiver capsules in the hand set.

The channel 4 is formed with a cross section which corresponds substantially to the cross section of the cord 5 which is threaded therein and lies across the bottom of the transmitter electrodes (not shown) of the transmitter. 'Ihe prongs to, I! are arranged symmetically with respect to the circular base of the transmitter capsule 5, the case of which is preferably made of molded thermoplastic material and is formed with a pair of diametrically opposite ridges l4,

I5 which fit in corresponding guiding grooves provided in the wall of the transmitter cavity 2 when the capsule is inserted in its'cavity. Since the transmitter is intended to be connected to the two outer conductors of the cord 5, the two ridges l4, l5 and their guiding grooves may be alike, as the transmitter may assume either of two positions displaced The act of screwing down the cap 8 presses the transmitter capsule 6 home in its cavity and forces the prongs I8, I! through the insulation of the cord 5 into the tinsel of the two outer conductors.

The receiver capsule l, the case of which is also preferably of molded plastic material, also has mounted upon its base a. pair of connectors also provided with rearwardly projecting prongs l2. it. The aforesaid connectors are electrically connected to the ends of the receiver coil (not shown). The prongs l2 and 13 are asymmetrically arranged with respect to a diameter of the circular base of the capsule, since it is desired that they make electrical contact with the center conductor and one outer conductor, re-' spectively, of the cord 5, as shown in Figs. 4 and 6. The casing of the receiver capsule! is formed with a pair of ridges l6, l1, and the wall of the receiver cavity 3 with corresponding guiding grooves, which are of different size to ensure that the receiver capsule I can be inserted into its cavity in one position only. The act of screwing down the cap 9 on the receiver capsule I forces the prongs l2 and I3 into the center conductor and one of the outer conductors.

.It will be appreciated that if desired, the

prongs associated with the receiver capsule may be arranged to make'contact with the two outer conductors, andthose of the transmitter capsule with the center conductor and one of the outer conductors of the cord 5. Moreover, if desired, only one guiding ridge and groove may be provided for ensuring that the transmitter capsu'le or the receiver capsule is, positioned cor-' 'hand 'set is in use;

1 A steel mandrel is used to core out the handle of the hand set to provide the channel 4 for the cord '5, and in order that it may be withdrawn from the molding it must be slightly tapered towards the receiver end, thus enlarging towards the transmitter end. Although, therefore, the cord 5'may fit snugly in the portion of the channel S'beneath the receiver capsule 1, there will be some slight play in the part of the channel beneath the transmitter capsule 6. In order, therefore, to compel the-centering of the cord "5 correctly beneath the prongs I 0, I I, the con-' tors threaded as a whole in said channel, a plurality of electrical connectors mounted on said shell therefor formed with a handle, a pair of cavities for accommodating said transmitter and nel open at one end'of said supporting shell and said receiver capsules respectively, and a chanextending through said handle from the base of said transmitter cavity to the base of said receiver cavity, a conductor cord comprising a plurality of parallel conductors threaded as a Whole in said channel, a plurality of electrical connectors mounted on the base of said transmitter capsule, and a plurality of electrical connectors mounted on the base of said receiver capsule, each said connector having at least one rearwardly projecting prong, said prongs being so positioned that when said transmitter and receiver capsules are pressed home into their respective cavities said prongs are forced into said cord to make electrical contact with the proper conductors.

tacting edges of the snubbers [8 are hollowed out r to conform with the contour of that side of the cord upon which they press when the cap 8 is screwed down. 'Ihe snubbers I8 may be constituted by molded projections on the base of the molded transmitter capsule casing. If desired, snubbers 'may also be provided on the base of the receiver capsule for a similar purpose. V

While I have described particular embodiments of 'my invention for the purposes of illustration,

it should be understood that various modifications and adaptations thereof may be made 7 within the spirit of the invention as set forth in the appended claims. For example, any one of thethree cord conductors may be employed .as the common conductor." Thus, the prongs on "one capsule may be so positioned as to make contact with the center conductor and one outer conductor and the prongs on the other capsule so positioned as to make contact with the center conductor and the other outer conductor.

What I claim is: V 1. A telephone hand set comprising a transmitter element, a receiver element, a supporting shell therefor formed with a handle, a pair of cavities for accommodating the transmitter and receiver elements respectively, and a channel 7 open at one end of said supporting shell and extending through said handle from said transmitter cavity to said receiver cavity, a conductor cord comprising a plurality of parallel conduc- 3. .A telephone hand set according to claim 2, wherein at least one of said capsules is provided on its base with at least one projecting member so shaped and positioned that when said capsule is pressed home in its cavity said projecting member engages and compresses said cord.

4. A telephone hand set according to claim2, wherein said transmitter capsule is provided on its base with projecting members so shaped and positioned that when said capsule is pressed home in its cavity said projecting members engage and compress said cord on each side of the connecting prongs provided on said transmitter capsule.

5. A telephone hand set according to claim 2, wherein said transmitter capsule is provided on its base with projecting members so positioned that when said capsule is pressed home in its cavity said projecting members engage and compress said cord in said channel on each side of the connecting prongs. provided on said trans-.

mitter capsule, the edgesof said projecting members being so shaped that during this operation they correctly center said cord beneath the connecting prongs provided on said transmitter capsule.

6. A telephone hand set according to claim 2,

ductor and one of the outer conductors.

8. A telephone hand set according to claim 2,

wherein said transmitter and receiver capsules, ar each provided with at least one guiding ridge and said transmitter and receiver cavities are each formed with at least one corresponding guiding groove so positioned as to ensure that said prongs on said transmitter and receiver capsules register with the proper cord conductors when the capsules are inserted and pressed home in their respective cavities.

9. A telephone hand set according to claim 2, further comprising peripheral lips on said transmitter and receiver capsules, seatings for said lips on said supporting shell at the edges of said transmitter and receiver cavities, and threaded caps formed with abutments which when said caps are screwed onto said shell force said lips against said seatings, the distance from the points of said prongs to said lips being such that when said lips are forced against their seatings by the act of screwing on said caps, the said prongs are forced into said cord and make electrical contact with the proper conductors.

10. A telephone transducer comprising a supporting shell, a transducer element, a cavity in said shell for accommodating said transducer element, a channel formed in the base of said cavity, a conductor cord comprising a plurality of parallel conductors positioned in said channel, a plurality of electrical connectors mounted on the base of said transducer capsule, each said connector having at least one rearwardly projecting prong, a peripheral lip on said transducer capsule, a seating for said lip on said supporting shell at the edge of said cavity, and a threaded cap formed with an abutment which when said cap is screwed onto said shell forces said lip against said seating, the distance from the points of said prongs to said lip being such that when said lip is forced against its seating by the act of vided on its ,base with projecting members so positioned that when said lip is forced against its seating said projecting members engage and compress the cord in said channel on each side of said prongs, the edges of said projecting members being formed with a recess conformin to the contour of said cord whereby when said cap is screwed onto said shell said members correctly center said cord beneath said prongs.

13. A telephone hand set according to claim 2,

wherein said conductor cord comprises three parallel conductors, said prongs on one of said capsules being so positioned as to mak contact with the center and one outer conductor, and said prongs on the other capsule being so positioned as to make contact with the center and the other outer conductor.

ERNEST S. McLARN. 

